Rabban Gamliel of Yavneh was a controversial leader. He excommunicated his own brother-in-law, Eliezer ben Hyrcanus. In a dispute about fixing the calendar, Rabban Gamliel humiliated Rabbi Joshua v. Hananiah and this led to a rabbinic revolt against Gamliel's leadership of the sanhedrin.
Rabbi Gamliel’s overriding philosophy was: Whoever has mercy on other people, Heaven will have mercy upon him; whoever does not have mercy on other people, Heaven will not have mercy upon him (Shabbos 151b).
Gamliel was extremely upset when he heard that the price for doves, which were necessary for certain sacrifices, had reached a golden dinar.
Rabbi Gamliel felt that it was very important for the sake of unity to ensure that all members of the Sanhedrin abide by the decision of the majority.
GamlielII was knowledgeable in many areas and the Talmud notes that he was an expert in intercalations, medicine, and Greek philosophy (Sanhedrin 11a, Berachos 25a, Sotah 49).
Rabban Gamliel grew into a learned but arrogant man. He freely employed herem (banning or excommunication) to force other rabbis to submit to his authority and the authority of the Sanhedrin (even placing his brother-in-law, Rabbi Eliezer ben Hyrcanus haGadol under a ban), although he was gracious and forgiving to those who did submit.
Gamliel became depressed, saying ‘Have I kept [words of] Torah from Israel?’ In a dream, he was shown white barrels, filled with ash – but that was not accurate, they only showed him that to restore his spirits (i.e.
Rabban Gamliel thought that he was doing a great work – using his power and authority to see to it that only worthy men would study Torah, and that frauds and hypocrites would not be allowed to use their studies as a pretext to oppress and deceive others.